Java 列表框JList

时间:2022-05-23 小旺不正经人气:0

Java程序设计图形用户界面【十一】列表框JList

列表框JList

JList常用方法

方法	作用
public JList(ListModel dataModel)	根据ListModel构造JList
public JList(Object[] listData)	根据对象数组构造JList
public JList(Vector<?> listData)	根据一个Vector构造JList
public void setSelectionMode(int selectionMode)	设置选择模式，是多选还是单选
public ListModel getModel()	返回列表框的列表模型
public int[] getSelectedIndices()	返回所选择的全部数组

可以通过ListSelectionModel接口完成列表框是多选还是单选

ListSelectionModel定义的常量

常量	作用
static final int MULTIPLE_INTERVAL_SELECTION	一次选择一个或多个连续的索引范围
static final int SINGLE_INTERVAL_SELECTION	一次选择一个连续范围的值
static final int SINGLE_SELECTION	一次选择一个值

import javax.swing.*;
import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.Vector;

class MyList{
    private JFrame frame = new JFrame("一");
    private Container cont = frame.getContentPane();
    private JList list1 = null;
    private JList list2 = null;
    public MyList(){
        this.frame.setLayout(new GridLayout(1,3));
        String n[] = {"A","B","C","D","E","F"};
        Vector<String> v = new Vector<String>();
        v.add("A");
        v.add("B");
        v.add("C");
        this.list1 = new JList(n);
        this.list2 = new JList(v);
        list1.setBorder(BorderFactory.createTitledBorder("请选择"));
        list2.setBorder(BorderFactory.createTitledBorder("请选择"));
        list1.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
        list2.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        cont.add(this.list1);
        cont.add(this.list2);
        this.frame.setSize(300,200);
        this.frame.setVisible(true);
        this.frame.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(1);
            }
        });
    }
}
public class Hello {
    public static void main(String[] args) {
        new MyList();
    }
}

第一个JList通过字符串数组设置列表的内容，并通过setSelectionMode()方法设置一次性可以选择多个选项

第二个JList通过Vector设置列表的内容，并通过setSelectionMode()方法将其设置成每次只能选择一个选项

使用ListModel构造JList

ListModel是一个专门用于创建JList列表内容操作的接口

方法	作用
void addListDataListener(ListDataListener l)	加入数据改变事件的监听
void removeListDataListener(ListDataListener l)	加入数据删除时的监听
Object getElementAt(int index)	返回指定索引处的内容
int getSize()	返回列表长度

import javax.swing.*;
import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

class MyListModel extends AbstractListModel{
    private String n[]={"A","B","C","D"};

    @Override
    public int getSize() {
        return this.n.length;
    }

    public Object getElementAt(int ind){
        if(ind<this.n.length){
            return this.n[ind];
        }else {
            return null;
        }
    }
}
class MyList{
    private JFrame frame = new JFrame("一");
    private Container cont = frame.getContentPane();
    private JList list1 =null;
    public MyList(){
        this.list1 = new JList(new MyListModel());
        list1.setBorder(BorderFactory.createTitledBorder("请选择"));
        list1.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
        cont.add(this.list1);
        this.frame.setSize(300,200);
        this.frame.setVisible(true);
        this.frame.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(1);
            }
        });
    }
}
public class Hello {
    public static void main(String[] args) {
        new MyList();
    }
}

JList事件处理

使用ListSelectionListener的监听接口实现对JList中所选项的监听

ListSelectionListener接口定义的方法

方法	作用
void valueChanged(ListSelectionEvent e)	当值发生改变时调用

ListSelectionEvent的常用方法

方法	作用
public int getFirsIndex()	返回选择的第1个选项的索引值
public int getLastIndex()	返回选择的最后1个选项的索引值

对JList进行监听

import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

class MyListModel extends AbstractListModel{
    private String n[]={"A","B","C","D"};

    @Override
    public int getSize() {
        return this.n.length;
    }

    public Object getElementAt(int ind){
        if(ind<this.n.length){
            return this.n[ind];
        }else {
            return null;
        }
    }
}
class MyList implements ListSelectionListener {
    private JFrame frame = new JFrame("一");
    private Container cont = frame.getContentPane();
    private JList list1 =null;
    public MyList(){
        this.list1 = new JList(new MyListModel());
        list1.setBorder(BorderFactory.createTitledBorder("请选择"));
        list1.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
        list1.addListSelectionListener(this);
        cont.add(this.list1);
        this.frame.setSize(300,200);
        this.frame.setVisible(true);
        this.frame.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(1);
            }
        });
    }

    @Override
    public void valueChanged(ListSelectionEvent e) {
        int temp[] = list1.getSelectedIndices();
        System.out.print("选的的内容是：");
        for(int i:temp){
            System.out.print(list1.getModel().getElementAt(i)+",");
        }
        System.out.println();
    }
}
public class Hello {
    public static void main(String[] args) {
        new MyList();
    }
}

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